In the past a number of different methods have been used for removing salt from sea water to produce substantially salt-free water supplies. A number of these procedural mechanisms are disclosed in U.S. Pat. Nos. 4,121,977 issued Oct. 24, 1978 to CARSON; 4,135,985 issued Jan. 23, 1979 to LAROCCA; 4,235,680 issued Nov. 25, 1980 to DIGGS; 4,270,981 issued Jun. 2, 1981 to STARK. These prior art systems require a great deal of energy and have not proved to be cost effective.